evolution

the change in the gene pool of a POPULATION over time

natural selection

the driving force of evolution and operates on the INDIVIDUAL

Charles Darwin

18th century, On the Origin of Species, finches

Jean-Baptiste de Lamarck

pre-Darwin WRONG theories that acquired changes show up in gametes

paleontology

the study of fossils

fossil dating

age of rocks around a fossil, rate of decay of isotopes, geographical data

biogeography

study of distribution of flora and fauna in the environment

embryology

the study of development of an organism

morphological homologies

the study of the anatomy (homologous and analogous structures) of various animals

homologous structures

same appendages that develop different purposes, point to common ancestor

analogous structure

features with the same function but different structures, evolved independently (e.g. insect and bat wings)

molecular biology

closely related organisms have a greater proportion of nucleotide / amino acid sequences in common

continuing evolution

evolution is constantly occurring with consistent small changes in DNA, fossil record, evolving pathogens

common ancestor

some original life form shared between two groups

phylogenetic tree (cladogram)

hypotheses used to study relationship between organisms

out-group

the least related group to all other species in a phylogenetic tree

genetic variability

no two individuals in a population have an identical set of alleles

peppered moths

example of directional selection, air pollution, black becomes prevalent over white

adaptation

a variation favored by natural selection

random mutation

internal advantage, initial variation is by chance but can eventually become an advantage only after something makes it apparent

environmental pressure

external sources causes a trait to be advantageous

evolutionary fitness

given to an organism with ANY trait that causes it to reproduce better

sexual selection

natural selection arising through preference of some trait that makes an individual more likely to be chosen for reproduction

genetic drift

something that causes a change in a population that is not natural selection (left over traits RANDOM, not necessarily advantageous)

bottleneck / founder effect

genetic drift, random events that drastically reduce the number of individuals in a population

gene flow

occurs between different populations of the same species with immigration or emigration of populations

directional selection

one phenotype is favored at one extreme of the normal distribution

stabilizing selection

organisms in a population with extreme traits are eliminated (middle is favored)

disruptive selection

favors both extremes and selects against common traits

artificial selection

humans directly affect variation in other species

species

two individuals able to mate and produce viable offspring that would be able to mate and produce viable offspring

reproductively isolated

two species who cannot mate, allowing them to undergo natural selection and evolve differently

divergent evolution

when different variation and environmental pressures cause a change that makes groups no longer able to mate

punctuated equilibrium

divergent evolution occurs quickly after a period of little evolution (stasis)

gradualism

divergent evolution that comes after many small changes over hundreds or millions of years

adaptive radiation

divergent evolution when a species rapidly diversifies due to an abundance of available ecological niches

pre-zygotic barriers

fertilization is prevented between two species

post-zygotic barriers

inability of hybrid organisms to produce offspring

convergent evolution

two unrelated and dissimilar species come to have analogous traits, because exposed to similar selective pressures

speciation

the formation of new and distinct species in the course of evolution

allopatric speciation

a population becomes separated from the rest by a geographic barrier, so the two can't interbreed

sympatric speciation

new species form without a geographic barrier

polyploidy

possessing more than two complete sets of chromosomes (plants)

Hardy-Weinberg law

even with all the shuffling of genes, the relative frequencies of genotypes in a population are constant over time (neither dominant nor recessive disappears)

Hardy-Weinberg equilibrium requires...

large population, no net mutations, no immigration or emigration (no gene flow), random mating (no sexual selection), no natural selection

p

dominant allele frequency

q

recessive allele frequency

p^2

homozygous dominant genotype frequency

2pq

heterozygous genotype frequency

q^2

homozygous recessive genotype frequency

Alexander Oparin and J.B.S. Haldane

primitive atmosphere of Earth contained mostly inorganic molecules, rich in gases with almost no free oxygen, gas collisions and chemical reactions led to organic molecules of today

Stanley Miller and Hardol Urey

proved Oparin and Haldane in lab with gases in a flask, charged, created organic compounds similar to amino acids

RNA-World Hypothesis

original life forms were simply molecules of RNA that could replicate and pass their genome along